Two recent studies indicate long-term immunity

1,700 Views | 3 Replies | Last: 5 yr ago by ElephantRider
Carolin_Gallego
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Quote:

Immune warriors known as T cells help us fight some viruses, but their importance for battling SARS-CoV-2, the virus that causes COVID-19, has been unclear. Now, two studies reveal infected people harbor T cells that target the virusand may help them recover. Both studies also found some people never infected with SARS-CoV-2 have these cellular defenses, most likely because they were previously infected with other coronaviruses.

"This is encouraging data," says virologist Angela Rasmussen of Columbia University. Although the studies don't clarify whether people who clear a SARS-CoV-2 infection can ward off the virus in the future, both identified strong T cell responses to it, which "bodes well for the development of long-term protective immunity," Rasmussen says. The findings could also help researchers create better vaccines.
Quote:

All of the patients carried helper T cells that recognized the SARS-CoV-2 spike protein, which enables the virus to infiltrate our cells. They also harbored helper T cells that react to other SARS-CoV-2 proteins. And the team detected virus-specific killer T cells in 70% of the subjects, they report today in Cell. "The immune system sees this virus and mounts an effective immune response," Sette says.

The results jibe with those of a study posted as a preprint on medRxiv on 22 April by immunologist Andreas Thiel of the Charit University Hospital in Berlin and colleagues. They identified helper T cells targeting the spike protein in 15 out of 18 patients hospitalized with COVID-19.
https://www.sciencemag.org/news/2020/05/t-cells-found-covid-19-patients-bode-well-long-term-immunity

Promising news.
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eric76
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AG
That does sound good.

I wonder how long the long term immunity they mention would be.
Carolin_Gallego
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A good question for which we all want to know the answer.

Also note that one of the studies showed a potential for cross-species immunity between other corona viruses and this one.
We believe progress is made through MORE discussion, not LESS, and we believe that to be true even if the topics are uncomfortable and we occasionally disagree with one another. - TexAgs
The name-calling technique making false associations is a child's game. The propagandist who uses this technique hopes that the audience will reject a person and their argument on this false basis.
plain_o_llama
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The underlying paper

https://www.medrxiv.org/content/10.1101/2020.04.17.20061440v1.full.pdf



Summary

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a rapidly
unfolding pandemic, overwhelming health care systems worldwide1. Clinical manifestations of
Coronavirus-disease 2019 (COVID-19) vary broadly, ranging from asymptomatic infection to
acute respiratory failure and death2, yet the underlying mechanisms for this high variability are
still unknown. Similarly, the role of host immune responses in viral clearance of COVID-19
remains unresolved. For SARS-CoV (2002/03), however, it has been reported that CD4+ T cell
responses correlated with positive outcomes3,4, whereas T cell immune responses to SARS-
CoV-2 have not yet been characterized. Here, we describe an assay that allows direct detection
and characterization of SARS-CoV-2 spike glycoprotein (S)-reactive CD4+ T cells in peripheral
blood. We demonstrate the presence of S-reactive CD4+ T cells in 83% of COVID-19 patients,
as well as in 34% of SARS-CoV-2 seronegative healthy donors (HD), albeit at lower
frequencies. Strikingly, S-reactive CD4+ T cells in COVID-19 patients equally targeted N-
terminal and C-terminal epitopes of S whereas in HD S-reactive CD4+ T cells reacted almost
exclusively to the C-terminal epitopes that are a) characterized by higher homology with spike
glycoprotein of human endemic "common cold" coronaviruses (hCoVs), and b) contains the S2
subunit of S with the cytoplasmic peptide (CP), the fusion peptide (FP), and the transmembrane
domain (TM) but not the receptor-binding domain (RBD). In contrast to S-reactive CD4+ T
cells in HD, S-reactive CD4+ T cells from COVID-19 patients co-expressed CD38 and HLA-
DR, indivative of their recent in vivo activation. Our study is the first to directly measure SARS-
CoV-2-reactive T cell responses providing critical tools for large scale testing and
characterization of potential cross-reactive cellular immunity to SARS-CoV-2. The presence of
pre-existing SARS-CoV-2-reactive T cells in a subset of SARS-CoV-2 naive HD is of high
interest but larger scale prospective cohort studies are needed to assess whether their presence
is a correlate of protection or pathology for COVID-19. Results of such studies will be key for
a mechanistic understanding of the SARS-CoV-2 pandemic, adaptation of containment
methods and to support vaccine development.

ElephantRider
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AG
"the studies don't clarify whether people who clear a SARS-CoV-2 infection can ward off the virus in the future"
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